The present invention relates to vehicle seat belt systems and components.
Current vehicle seat belt designs are generally of the three point type wherein three anchoring points are provided for two lengths of belt. The two lengths of belt are referred to as the lap belt and shoulder belt. The two lengths of belt are both connected to a single latch mechanism located adjacent a seat occupant""s hip. The seat belt latch includes one portion that is connected to the lap and shoulder belt. The other end of the latch is non-extensibly mounted to the seat structure or a seat belt latch presenter that holds the latch at a fixed location.
Four point and five point seat belts have been used in race cars and by airplane pilots but have not been accepted for normal passenger car and truck applications because prior designs were difficult to use. With four or five point belt systems, the preferred location of the latch is a mid-body position that allows for a symmetrical belt arrangement and convenient single latch mechanism. It would also be helpful to provide a four point seat belt latch mechanism that may be operated by one hand and that would minimize difficulties relating to aligning the two latch parts to secure the latch parts together.
Another problem unresolved by prior art four point belt systems is providing for a simple and effective belt presentation system that makes it convenient for vehicle seat occupants to locate and operate the seat belt latch.
These and other problems and disadvantages associated with prior art seat belt systems is addressed by applicant""s invention as summarized below.
According to one aspect of the invention, a self-centering, equalized seat belt retractor is provided. Two seat belt retractors are provided for two independently movable belt segments, preferably two lap belt segments, that are linked together by means of a torsion spring. Each of the retractors includes a separate spool on which a belt segment is wound to retract the belt and unwound to allow the belt to be extended from the retractor. One retractor rotates in a clockwise direction to retract the belt while the other retractor rotates in a counterclockwise direction to retract its associated belt segment. The spring is provided to equalize the retractive force exerted by the seat belt retractors on the two belt segments which also causes the latch mechanism to be centered relative to a seat occupant""s body. The two linked belt retractors are preferably mounted on the floor or on the lower seat structure of the vehicle seat. The seat belt retractors include an inertial locking pawl or brake that locks the retractors in the event of an impact.
According to another aspect of the invention, belt presenters are provided on a vehicle seat for presenting two parts of a seat belt latch when a person initially sits down in the vehicle seat. Weight sensors provided in the vehicle seat activate the seat belt presenters. The seat belt presenters comprise arms on opposite sides of a vehicle seat that are pivotally connected to opposite sides of the vehicle seat. The arms pivot from a first position wherein the seat belt latch is grasped by a magnet, hook, or other grasping device. When a person initially sits on the vehicle seat, the seat belt presenters are in their first position. Upon sensing the presence of a person""s body in the seat, the seat belt presenters rotate to the position where the seat belt latches held by the seat belt presenter are moved to an easily accessible position forward of the person""s torso and above the person""s lap. The seat belt latches may then be conveniently gripped by the seat occupant and released from the belt presenters. When the seat belt latches are engaged with each other, a seat belt latch sensor provides a signal to the belt presenter to return the belt presenters to their first position. When a person is ready to leave the vehicle seat, they merely unbuckle the seat belt latch allowing the retractors to return the two parts of the seat belt latch to their retracted position adjacent to the end of the seat belt presenter. The seat belt presenter then grasps or engages the seat belt latches so that the belt presenters are ready to repeat the cycle.
The above aspects of the various inventions disclosed will be better understood in view of the attached drawings and following detailed description of various modes of the invention.